VEGETABLE FIBRE ROPESVegetable fibre ropes are made from the following material. Manila: This fibre is extracted form leaves of the Abaca plant and is golden in color. Manila ropes are strong and reliable. They are use for mooring hawser, slings Derrick guys, tow ropes gantlines, aloft works and wherever else reliability is required and risk of life is involved.

• Sisal: Sisal ropes are not as strong and reliable as manila ropes but being comparatively cheaper, they are used for general work such as lashing etc. but not where a parting of the rope is liable to kill or miam somebody. Sisal fibre is pale yellow in color, Like straw, and is obtained from the leaves of a cactus-like plant.

• Hemp: This fibre is obtained form hemp plant called agave sislana and is grey in color. It is the strongest amongst vegetable fibre and used for signal halyards. Boat lacing, Log line, Lead line etc.

• Coir: This fibre is obtained from coconut husk and is brown in color. Coir rope are hairy, light and cheap. Although it is the weakest of all ropes and very light in weight it floats on water used for buoying an anchor.

• Cotton: Cotton ropes are not strong and rot easily. Therefore, they are not in common use on ships except for decorative purpose.

HAWSER LAID ROPE

• It is a right handed three strand rope. It is most popular on ships and is the strongest of all stranded ropes.

SHROUD LAID ROPE

• This rope is right handed with four strands laid around a central heart. It is 10% weaker than a hawser laid rope of the same size.

CABLE LAID ROPE

• It composed of three hawser laid ropes, laid left handed to make a 9 strand rope. Since the breaking strength decreases as the total number of strands in a rope increase beyond three, a cable rope is 40% weaker than a hawser laid rope of similar size. It absorbs less water and is very elastic. It was, therefore, once widely used for towing springs and hand lead line.

CONSTRUCTION OF VEGETABLE FIBRE ROPES

• The fibres are first cleaned and combed to make them straight called ribbons. They are then, for a right handed ropes, twisted right handed to form yarns. Yarns are twisted left handed to form Strands. The strands are then laid up right handed to make a rope. The direction of the twist is reversed for left handed rope. On a ship generally, right handed ropes are used except for the hand lead line.

STEEL WIRE ROPES

• Wire rope construction is indicated mainly by number of strands and number of wires in each strand. For example when you hear 6 by 24 written as 6x24 it means the wire consist of 6 main strands and 24 main wires in each strand. Thus the figure 6x12, 6x24, 6x37 denote that the rope has 6 strands of 12, 24 or 37 wires in each wire rope.

CONSTRUCTION OF WIRE ROPE

• A number of thin wires are twisted left handed to form a strand. Six such strands are then laid up right handed around a central heart. The heart can be either of vegetable fiber or synthetic fiber or a wire rope. Vegetable fiber heart absorbs oil when the rope is oiled and later when the rope is under stress, some oil is squeeze out and lubricate the wires. But it also absorbs and retains water, which damages the wire therefore , some brands of wire ropes have a polypropylene heart.

MEASURMENT OF ROPES

• Ropes are measured by their diameter. The size of a rope is its diameter in millimeter. To measure the size of a rope take a length of twine and wind it around the rope once or twice. Then with a pen draw a vertical lines over the turns of the twine. Unwind the twine and measure the distance between any two ink marks. This is the circumference of the rope, divide it by 22/7 to get diameter. Thus is a size of the rope. Also you can measure the size with the vernier caliper.

FRENCHMAN LOOP

• Wire ropes are not so flexible and , therefore, they cannot absorb any twist. As far as possible a wire ropes should be coiled on a reel. But if a reel is not available, the rope may be coiled right handed on deck over a wooden grating. When thus coiling a used wire ropes, it will be found that it is not convenient to keep every loop on top of previous loop. Every now and then a loop has to be kept under the topmost loop. Such lops are called “frenchman loop”.

CARE AND MAINTENANCE OF SYNTHETIC FIBRE ROPE

• Rope should be stored in a dry well ventilated place, away from hot bulkheads.

• Coils should be stored on gratings and wet rope should be dried before being put away.

• Life of a rope will be shortened by chaffing and uneven wear caused by bad leads, such as by usage of a block too small for the size.

• Ropes should be stowed in separate compartment form containers of chemicals, paint and rust removers and other substances capable of damaging them.

• Synthetic ropes should not be exposed to sunlight for prolonged period.

• Ropes should be inspected carefully before use for signs of deterioration, undue wear or damage.

• Ropes should be never be subjected to bad nips.

• Avoid causing kinks in ropes, since they cause permanent injury to the ropes and reduce strength.

• Ensure fair leads and warping drums are in good condition, and free from rust and paint. Roller heads should be well lubricated, and freely moving to avoid friction damage to the rope.

• Do not drag ropes along the deck. If it is unavoidable, ensure they pass clear of sharp edges or rough surface.

• When using winch stored ropes, do not run them through leads, which are not in a direct line form the drum , as they are liable to chaff on the edge of the pool.

• Do not surge ropes around drum ends or bitts, as the friction temperature generated may be high enough to melt the fibers.

OPENING OF NEW COIL

• The method used for opening a coil of vegetable fibre rope by pulling out the end and running away with it can not be used for a wire rope as it will lead to kinks; and a kink once formed in a wire ropes can never be completely removed. Therefore, coils of wire ropes should be opened care fully by use of turn table or unroll on the deck or else a iron rod inserted through the centre of the coil makes the unrolling easier.

CUTTING A WIRE ROPE

• If a wire rope is cut as it is , the ends will fly apart. Therefore, before cutting make two strong whippings about 5 cm apart on either side of the place where the rope is to be cut. Put the wire rope on some solid steel structure and cut with a cold chisel with a handle. A cold chisel is a chisel with a very hard cutting edge.

FLAKING AND CHEESING DOWN ROPES

• In order that a rope may run out freely and fast, it should be flaked down as shown. The bight at the ends of the flake that will run out first, should be on top of the flake that will run out next.

LAY OF ROPE

• Ropes may be left handed or right handed to Know hold a rope vertically in front of you. If the strands run up from left to right it is right handed rope or ‘Z’ twist. If the strands run up from right to left it is left handed rope or ‘S’ twist. Only stranded ropes have a lay.

OPENING OF NEW COIL

• New line is coiled, bound, and wrapped in burlap as a protective covering. The burlap covering should not be opened until the line is to be used. To open, strip back the burlap wrapping and look inside the coil for the end of the line. It should be at the bottom of the coil. If it is not, turn the coil over so that the end will be at the bottom. Put your hand down through the center and grab the end of the line. Pull the end of the line up through the center of the coil. As the line comes up through the coil, it will unwind in a counterclockwise direction.

MONKEY FIST KNOT

• The monkey fist is tied at the end of a heaving line and a weight is put in it so that it can be thrown for a distance with some ease and accuracy. The monkey fist consists of three sets of turns taken at right angles to each other. For clarity, shows only three turns in each set; four turns per set are more likely to be used. To tie a monkey fist, start as in view 1, taking a set of turns around your hand. Then slip this set off your hand, hold it as shown in view 2, and pass the running end over your thumb and under and over the first set. Complete this set of turns. Put the last set around the second and through the first as shown in view 3. Note that the first turn of the last set locks the first two sets in place.